Posted
by
timothy
on Thursday April 01, 2010 @10:20PM
from the set-things-in-motion dept.

jcr writes "CNET and the Huffington Post both reportthe death of Henry Edward Roberts, best known to all of us as the inventor of the Altair computer, at the age of 68 from pneumonia. As it happens, I never got to use an Altair, but I did meet Ed once, back in the mid-1980s. Since that time, I've never referred to the Altair bus as the 'S100' bus, since I agree with him that an inventor is entitled to name his invention."Updated 7:40 GMT by timothy: Roberts was 68, not 88 as originally stated; thanks to the readers who pointed out the typo.

He invented also a device that moved him back 19 years. And his bio dont tell about the years he was hidden fearing facing his younger self. So we must thank him for personal computers and that the universe didnt got destroyed by a paradox.

Of course it was not octal. it was binary. there were 16 switches across the front.

these days most people represent binary numbers as hex. Ever wonder why Octal used to be so much more popular? when you write octal numbers they are really inconvenient so why use them?

Well the answer is, if you are keying in binary number in one switch at a time you can do it lightning fast in octal but not in hex.

with octal you use your middle, index and ring fingers and you can whip the switches up an down. While you do have four fingers you can't easily use all four fingers to slap the switches

try it, your fingers are not equally long, and it's hard to retract your fingers in all 16 possible positions.

octal is easy.

So you programmed altairs in octal.

the altair I used did not even have a boot loader. you just toggled in the binary to enter the boot loader then once you had that in you could read the casstte which had a longer more sphisticated boot loader. which then read in BASIC.

there was no OS. if you wanted an OS, you wrote it in basic as you needed it.

to enter the program into memory the altair used an interesting trick. the front panel switches could set the address counter to an address, which could then be incremented. You put the computer into a wait state to enter the data to be written to the memory, then advanced the address counter.

by the way the 6502 was a much better processor with a simpler but more sophisticated instruction set.

one reason I think the 8080/Z80-series beat the 6502 was an early version of the megahertz myth. The 4mhz base clock rate of the z80 was faster than the 6502's base clock rate of 1Mhz. But the z80 used 4 clock cycles and a few wait states for most instructions. the 6502 complete nearly every instruction in one instruction.

if only the altair had been 6502 based.

(the 6502 came out later in time of course, so it's understandable.. and there was a 6800-series version of the altair that never caught on).

Having learned Assembly on a Dec PDP8 back in the mid 1960's I was struck by how similar the Altair 8800 looked to that machine. The Dec had fancier switches and we had a paper tape reader and a model 33 TTY for output. However, you STILL had to key in the FIRST (of two I think) boot loaders by hand in Octal on the front panel. Octal has NOT gone away, however. ALL IPV4 addresses are really OCTAL numbers. If you can think in Octal and know how an XOR gate works then Net Masks make perfect sense.

these days most people represent binary numbers as hex. Ever wonder why Octal used to be so much more popular? when you write octal numbers they are really inconvenient so why use them?

Well the answer is, if you are keying in binary number in one switch at a time you can do it lightning fast in octal but not in hex.

with octal you use your middle, index and ring fingers and you can whip the switches up an down. While you do have four fingers you can't easily use all four fingers to slap the switches

Interesting, but I don't think that's the only reason octal used to be more popular than hex.

Although hexadecimal was introduced very early in computer history, it was generally rejected early on. There was little agreement on how to represent digits greater than 9, and it seems many people found the idea of using letters for numerical digits to be highly objectionable.

Octal didn't have that problem, and it was a natural fit for computers of the 1950s and early 1960s. Many of these used 6-bit characters (upper case only) and had word sizes which were multiples of 6. For example, all of DEC's systems developed before the PDP-11 had such word sizes, as did IBM's 700 and 7000 series of scientific systems. On such systems, words and characters would cleanly fit into an even number of octal digits.

Even on the PDP-11, which had 16-bit words and 8-bit characters, octal was still preferred. The PDP-11's binary instruction format, which had 3-bit specifiers for its registers and addressing modes, made it much simpler to read and write PDP-11 machine code in octal than in hex.

IBM's System/360, which had 8-bit characters, 32-bit words, and byte-addressable memory, had a big effect in making hexadecimal popular in the computing world, but it took time for the shift to fully take place. I think part of the reason octal was still used with the Altair was persistence of octal's old dominance.

one reason I think the 8080/Z80-series beat the 6502 was an early version of the megahertz myth. The 4mhz base clock rate of the z80 was faster than the 6502's base clock rate of 1Mhz. But the z80 used 4 clock cycles and a few wait states for most instructions. the 6502 complete nearly every instruction in one instruction.

I'm not sure why you think the 8080/Z80 "beat" the 6502. While it's true that many early 8-bit microcomputers were based on the 8080 and Z80, especially in the CP/M world, some very po

I think you're confusing "memory cycle" with "instruction cycle". By "memory cycle", I mean a single bus access to memory: the memory address gets put on the bus, and then the data value is received or sent. Most Z80 and 6502 instructions require several such accesses: 1 to fetch the opcode byte, possibly additional ones to fetch further operation bytes, if any, followed by memory accesses for operand fetch and/or writing the result.

The Z80 I had took four clock cycles for the first memory access (the first byte of the instruction) and three for each following memory access. There were a few exceptions, but overall that was pretty accurate. There were instructions that took four cycles.

On the 6809, first memory access was two cycles, with one for each remaining one. Again, there were exceptions. The 6809 was a somewhat later chip, and had assembler compatibility with the 6800 rather than the almost complete binary compatibility

The Z80 I had took four clock cycles for the first memory access (the first byte of the instruction) and three for each following memory access. There were a few exceptions, but overall that was pretty accurate. There were instructions that took four cycles.

*goes back and checks*

Argh, you're absolutely right. It was 3 to 4 cycles, not 2 to 3. That's what I get for trusting my own memory rather than checking it. Thanks for setting that straight.

I'm not sure why you think the 8080/Z80 "beat" the 6502. While it's true that many early 8-bit microcomputers were based on the 8080 and Z80, especially in the CP/M world, some very popular and successful 8-bit systems used the 6502, like the Apple II, Commodore 64, and Atari's home computers and game consoles.

Well, you likely wrote that on a computer which uses a descendant of 8080. There's also still quite a bit of Z80 around us, or so I've heard. 6502 lineage...died out.

Yeah, but that doesn't sound like what the original poster meant by "beating the 6502", nor would I count it as such. I think it's misleading to use the future development of the architectures as arguments for competitive strength or weakness of their ancestors. During the 8-bit computer era, the 6502 was a very strong competitor to the Z80. True, the 6502's descendants ceased to be major players, but that's a different issue from the 6502's own competitiveness in its heyday.

I used to think the 6502 was superior for its lower clocks-per-instruction, but I've since learned more. The 6502 uses a two-phase clock, so it's really double the apparent clock rate. The Z-80 uses a higher clock, but runs memory at a lower rate. That was one of the limiting factors of those days, the speed of the external bus. So you could use the same speed memory with a 4 MHz Z-80 as with a 1 MHz 6502 (don't know the exact numbers, but it's basically like this). The Z-80 also had more registers and you

Download the archive, then use the contact form [blackbeltsystems.com] on blackbeltsystems.com to write to me, and I'll get you going. You'll probably enjoy it - it's very fast and there is a metric f-ton of software on the (virtual) disks that come with it. Assembler, editors, commands, etc.

It works on XP or earlier for sure; I gave up on Windows after XP, so it's possible it'd have to run in a compatibility mode or something under Vista or 7. Or not. I didn't break any rules that I know of when I wro

to enter the program into memory the altair used an interesting trick. the front panel switches could set the address counter to an address, which could then be incremented. You put the computer into a wait state to enter the data to be written to the memory, then advanced the address counter.

Interesting post. Older computers operated similarly to this. The altair was really a throwback to the early days of computing where registers were entered by hand via switches and the program or rather the machine cou

I remember those days, and you're right about keying octal. I remember being amazed at how fast I ultimately loaded the cassette bootloader in memory! I seem to remember something like 1444 bytes free after loading the BASIC interpreter.

Depends on the Month as well as the year. I was born 1949 and by your figures (2010-1949) I should be 61. I was born in late December of 49 and my age is 60 at present, which it will be until my birthday in December.

The Altair really got the hobby computer market going. It was by no means perfect, but it was something that a lot of people were hungry for. I had the thrill of working in a retail computer store in 1978 when the IMSAI and Apple were going head-to-head. [IMSAI is a spelling error in this text entry box, which tells you who won.]

(I'd rewrite that to correct for a missing "and" in the first sentence, and a missing "losers" in the second, but my vodka martini with a couple of lovely marinated olives says I don't want to. Arguably, this makes me a loser, but then: "Adolf" passes spellcheck just fine. Please moderate accordingly, whatever that means.)

I read a pretty interesting book about IMSAI a while back, and how they self-destructed. Apparently, their management was all caught up in the "EST" cult, so they simply ignored any negative information at all. Instead of dealing with problems, they fired anyone who insisted on mentioning them.

Hah, that's the first thing I thought of also! You're correct, he did indeed. And, if you're interested, you may be able to purchase the one used in the movie: http://www.imsai.net/Movies/WarGames.htm [imsai.net]

I just heard some sad news on talk radio - Computer engineer Ed Roberts was found dead in his Maine home this morning. There weren't any more details. I'm sure everyone in the Slashdot community will miss him - even if you didn't enjoy his work, there's no denying his contributions to popular culture. Truly an American icon.

And initial reports confirm that the death was not AIDS-related, as many had first feared. It would truly have been a blow to his legacy had being HIV positive been a contributing factor in this matter.

And initial reports confirm that the death was not AIDS-related, as many had first feared. It would truly have been a blow to his legacy had being HIV positive been a contributing factor in this matter.

--
I completely disagree with every word of the above post.

I'm glad you put that sig there. Because I don't see why being HIV positive would be a blow to someones legacy or even affect your look on someone.

Sometime around 1987 or so, he was working on a startup called "Georgia Medical Electronics", and his plan was to make very cheap, stackable modules that had an Altair-bus on the top and the bottom, so you could snap a CPU together with a disk module and a power control module and have a simple process control computer for a factory (for example). My partner at the time was one of the few people left who remembered how to write a CP/M BIOS, and we went down to Atlanta to talk to him about working together. It didn't pan out, but I was glad to get the chance to meet him.

- What about the internet? Do ya like the internet?- Oh, lolcats! No, no lolcats. Everything these days is lolcats. Lolcats and a lot of noise. Nobody even knows how to type. Just l33t speak and Rick Roll each other.

On this topic, anyone remember the 16-bit version of this bus? Anyone remember the S-100 8086 processor cards from SCP and CompuPro (and I am sure other vendors too)? Anyone remember playing with SCP 86-DOS before it got bought by MS for the IBM PC? What about CompuPro's S-100 286 processor card? They even made a 386 card using a connector at the top to expose the extra lines to other card. What about CP/M-86? Anyone want to predict what would have happened if IBM were able to license CP/M-86 from DR and pu

According to French Wikipedia, that'd be " Je vais ou je vas mourir, l'un et l'autre se dit ou se disent." It also says the story is made up.

Well, it's not really made up, just embellished a bit. I'm sure he would have said that if he'd had time. What he actually said was "Je vais ou je vas ACK" - but that didn't make for a very good final quote so they extrapolated a bit.

A friend built one. Pretty cool machine - well designed and it worked very well. I waited and built a SOL machine for myself and it was lots of fun, too. I was "lucky" enough to have an ASR-33 to hook to it and loaded programs from paper tape. With a 32K expansion board I could run 32K Basic and there were many evenings when I started the machine up, loaded the OS from tape then put the 32K Basic tape in the reader, hit start, and went out for dinner. Assuming nothing went wrong it'd be at a READY prompt in a little over 1/2 hour.

What's kind of funny in a strange way is that 32K Basic was a Bill Gates project. I remember having a problem one day, calling for help and speaking with him on the phone about it. He solved my problem for me - and I never imagined that things would turn out the way they have. The days are long gone when you'd toggle in the bootloader from the front panel - or get technical support from Bill Gates.

Things have changed a lot since then - I'm still quite amused by the current crop of "hackers" who think they're all that but never built their own computer from chips and raw PC boards. Building a PC these days is something grade school kids can do.

I'm still quite amused by the current crop of "hackers" who think they're all that but never built their own computer from chips and raw PC boards.

Think that's bad? I knew someone who was a manager of a software test group at HP who didn't even understand basic household wiring. He had a hell of a time grasping how a simple three-way switch works.

And I’m still quite amused by the current generation, who never planted and hunted and butchered their own food, never built their own house and car, and wouldn’t survive a day in the wilderness.;)

Times have changed. I designed my own tiny computer, and did a lot of system programming in the days before graphics, sound and chipset drivers.But there is an ideal in programming: Don”t re-invent the wheel!There is no point in writing your own standard library, if you already have a perfectly

I have designed and built my own random-logic boards and 25 years ago before university I designed and wire-wrapped a robotics system and OS that was seen on TV and got lots of investment, etc, etc, but I'm still pleased as punch these days to be able to get a SheevaPlug running an entire Linux with full IP stack, etc, in a smaller volume and with lower power consumption which itself can host Java with its extensive API libraries...

I'm still quite amused by the current crop of "hackers" who think they're all that but never built their own computer from chips and raw PC boards. Building a PC these days is something grade school kids can do.

I've been thinking that for a long time now, even though I didn't start that far back myself.

I started with the z80-based ZX Spectrum, and then graduated through a series of early PCs. The earliest one running GEM with a hercules (monochrome) graphics card.

It isn't bad, I just feel a little disappointed that computers are commodities these days and people don't need to understand things.
Sure it is a form of snobbery, and I'm sure there are similar groups such as mechanics who feel very similar.
But over time we've evolved into a situation where people are no longer encouraged to experiment, or use trial & error to solve computer problems. You see this most obviously in schools where kids are taught little "recipes" on how to use Microsoft Office, but

You think you had it hard waiting for paper tape? My brother wrote his own 2K Tiny Basic interpreter for the M6800 from scratch, stored on reel-to-reel tape. We wanted a printer; Dad brought home a Friden Flexowriter and invited us to make it talk. We did. We were lazy enough to ask for a 4K RAM kit with a genuine PC board for Christmas, since wire-wrapping 32 chips was a bit tedious.

Reminds me of when I was developing on SBC-80 systems based on the Intel 8080 back in the '70's. I was doing everything in machine code, typing it in on a teletype and using a simple monitor program from Intel. I had a big program, maybe Basic or some other simple "high level" language that I loaded via paper tape. I needed to move the program to another place in memory. So I copied the program using the monitor (program) and then wrote my own little program to change all the addresses in the code to ma

Our homebrew machine could play chess, play Star Trek, act as a word processor (my mom typed her thesis on it), we played 3D stereo Space War on an oscilloscope dot display, etc. It could do amazing things, all in 4K of RAM and a homemade 32x16 character display.

I'm not saying those weren't fun times, with amazing new things possible.

But keep it in perspective - how good game of chess that machine could do? How advanced & usable word processor was? (really better than good typewriter?)Or most importantly, from another angle, look at the things common people regularly do on current PCs. HD video editing? Photo editing? Quite smooth access to huge number of info kept on other computers (somewhat possible in old times after all...but, in comparison, almost nonexis

SWTPC 6800. An acquaintance had bought one, built most of it, and had several memory cards to build. He had run out of desire to solder chips, so he let me take it for a month to build the memory boards and test the system. I had a Teletype and a soldering iron, so I spent a month of my summer vacation playing with it (building the memory boards took only a day or two).

Real Computers have switches and lights.Real Hackers design and build their own computers.

This man did many things and touched many lives. Bill Gates's and Paul Allen's, included. FTA:

Roberts founded Micro Instrumentation and Telemetry Systems, which sold the kits. A young Gates and Allen would later found their fledgling Microsoft firm in Albuquerque, N.M., where MITS was based, and provide a computer language that helped hobbyists program and operate the Altair.

After selling his company, he tries both farming, and then medicine. (He's in his 40s at this time.)

He sold his company in 1977 and retired to a life of vegetable farming in rural Georgia before going to medical school and getting a medical degree from Mercer University, in 1986.

I'm still wondering when someone is going to make a "handheld" Altair, reproducing some of the looks and most of the functions (except for plugin cards) and selling it on ThinkGeek or somesuch for a reasonable price.
I want to play around with an Altair, but I'm not going to get one of those huge replicas:
http://www.altairkit.com/index.html [altairkit.com]

I believe that Briel Computers, the guys who designed the Apple 1 replica, The Replica-1 computer and other cool kits are working on something similar. The first version was a standard ATX case that was shaped like a Altair and the front panels were a controlled by a reprogrammable Microcontroller acting as an 8800 emulator. I am not quite sure of the specifics. http://www.brielcomputers.com/altairpc.html [brielcomputers.com]

After looking on his site, it seems they are now working on something similar to a handheld Altair calle

The man was one of the pioneers of the industry. I sure wish I could find one of those original 8800's to stick on a shelf. Maybe make it do one of those Cylon-like LED scans back and forth!
Talk about bringing back memories! I worked on one of those in school, repairing and calibrating the cassette interface! It's what got me hooked on computers. As I recall, after manually entering the boot-loader via the toggle switches and loading BASIC off the cassette tape we had 1444 bytes free or something like